The present invention relates to a pressure regulator for a high-pressure rail of a system for injecting fuel into an internal combustion engine, comprising a solenoid valve body, which accommodates a solenoid, which controls the needle that closes the valve seat, which is connected to the high-pressure inlet and opens into a discharge chamber, which communicates through outlet apertures with the liquid return circuit, wherein the rear side of the solenoid valve body accommodates the coil, which controls the opening of the rotor or armature, which is fixedly connected to the needle and is subject to a closing return spring, wherein the front side of the solenoid valve body, in the axis of the needle, comprises the discharge chamber, which extends through a cavity accommodating an inlet valve body, passing axially through which is the bore which opens into the valve seat, wherein this valve body is flanged into the cavity, wherein the discharge chamber, through which the needle axially passes, and the outlet apertures, which are connected to the liquid return circuit, open transversally into the wall in the discharge chamber below the upper part of the chamber.
A pressure regulator of the type defined above already exists. This known regulator has the disadvantage that it does not allow any optimization of the flow/pressure curve, which is in theory linear but which in practice is subject to an abrupt increase in the gradient, owing to the static pressure in the upper part of the discharge chamber.